Estimation of Hamaker Constants of Ceramic Materials from Optical Data Using Lifshitz Theory

Abstract

The Hamaker constants of eight different ceramic materials, 6H‐SiC, tetragonal, partially stabilized ZrO2 (3% Y2O3), β‐Si3N4, α‐Al2O3, Y2O3, sapphire (single‐crystal α‐Al2O3), MgO, MgAl2O4, and fused silica, across air, water, and n‐dodecane at room temperature and across silica at 2000 K have been calculated from optical data using the Lifshitz theory. Spectroscopic ellipsometry was used to measure the photon energy dependence of the refractive index, n, and the extinction coefficient, k, in the visible and near‐UV range on several important ceramic materials. This relatively simple, nondestructive technique has proved to yield reliable optical data on sintered, polycrystalline materials such as Si3N4, SiC, ZrO2, Al2O3, and ZnO. For the other materials, Y2O3, sapphire, MgO, MgAl2O4, and fused silica, optical data from the literature were used to calculate the Hamaker constants. The calculated Hamaker constants were estimated to be accurate within ±10%.

Comparisons of Hamaker Constants for Ceramic Systems with Intervening Vacuum or Water: From Force Laws and Physical Properties

“…In the derivation of the substantially less than required for the full spectral method. TWA, the electronic structure of a material was modeled as Bergström et al (49) used this technique to estimate Haa single oscillator. The oscillator frequency was assumed to maker constants for several ceramic materials separated by be constant and possess the same value for all materials.…”

Analysis of Particle Size Distributions of Quantum Dots: From Theory to Application

“…To illustrate this, Fig. 7 shows the deconvolution results of absorbance data derived for small (a, b) and large (c, d) ZnO QDs using two different datasets for the bulk absorption coefficient (Bergström L. et al, 1996;Yoshikawa H. and Adachi S., 1997). For validation, TEM and DLS results are presented as well.…”

Optical emission and absorption spectra of Zn–ZnO core-shell nanostructures

“…Therefore, the transitional absorption peak, appeared from fabricated Zn-ZnO nanostructure by consecutive lowering the power of laser ablation, might be attributed to exciton absorption from nanocrystalline or amorphous phase of ZnO shell and core metal interband absorption coupling. It is noted that compared to the usual absorption spectrum of ZnO [26,27], the absorption in the visible region of Zn-ZnO system seems to be strong. Generally, ZnO is transparent in the near infrared (NIR) and visible regions but an absorber in the UV region.…”